Automated non-invasive blood pressure (NIBP) monitoring is essential for the management of hypertension. The oscillometric technique is the main method used by automated NIBP monitors for clinical and ambulatory blood pressure (BP) monitoring, as well as self-measurement of BP. However, the oscillometric method is susceptible to error in certain clinical circumstances, particularly in elderly patients with stiff arteries due to atherosclerosis. A few factors are know to potentially influence the accuracy of oscillometric BP measurement: arterial stiffness, heart rate, pressure pulse amplitude, level of subject anxiety, cuff size, and cuff placement. Studies on biomechanical properties of the cuff-arm-artery system with numerical simulation have demonstrated that arterial stiffness is the main factor affecting the accuracy of oscillometric BP estimates, leading to errors as great as 15-20% in the computation of systolic blood pressure. Other studies also confirmed that arterial stiffness is the cause of disagreement between the oscillometric BP monitor and the sphygmomanometer. With the increase of an aging population leading to increased applications of oscillometry based NIBP monitors, there is an urgent need to develop better algorithms that improve the accuracy of oscillometric devices. The goal of this SBIR proposal will be to develop, validate, and commercialize an automated NIBP monitor, implementing NIBP algorithms that incorporate parameters to compensate for arterial stiffness. The success of this project will improve the accuracy of automated oscillometric NIBP monitors.